Due to rising oil prices and environmental concerns with increased emissions, a number of alternative fuels and fuel additives have been developed. A number of different approaches have been investigated to increase the efficiency of fuels and reduce emissions. Examples of alternatives to fossil fuels include the use of natural gas, propane, and electricity. Although these are viable substitutes for petroleum based fuels, they require a large investment in automobile modification and infrastructure to implement these technologies.
Another approach involves the use of alcohols in combination with fossil fuels. Alcohols have good combustion properties and are readily available. For example, ethanol can be obtained from a wide variety of sources such as, for example, starchy grains, potatoes, industrial by-products, and products of waste materials. Although the use of ethanol in combination with fossil fuels is a viable option, there are some drawbacks with its use. When ethanol is blended with hydrocarbons, the resulting mixture has an unacceptably high rate of evaporation, which may restrict its use in certain regions having strict emissions restrictions. Gasoline blended with ethanol is very sensitive to water, which can result in limited phase stability. Limited phase stability can result in significant engine problems such as, for example, such as stalling, fuel-line freezing, and the like.
The use of other alcohols has been investigated in view of the limitations associated with ethanol. For example, the use of methanol is one way to increase the octane number and reduce emissions. However, the use of higher amounts of methanol requires modification of the engine to avoid damage during combustion. For example, in order to operate an internal combustion engine having spark ignition with a combustion fuel containing more than 5% by volume of methanol, the engine has to be equipped with methanol-resistant sealing materials. Moreover, similar to ethanol, methanol has a high affinity for water, which can lead to phase separation when combined with gasoline.
Therefore, it would be desirable to have a fuel that burns cleaner (i.e., reduced emissions) and is more efficient (e.g., increased miles per gallon and horse power). It would also desirable that the use of the fuel does not require any modifications to the existing engine or require advanced technology to use the fuel. The modified fuels described herein address these needs.